The present invention relates to inclusion compounds of a vanillyl alcohol derivative (which may hereinafter be abbreviated as xe2x80x9cVExe2x80x9d), and compositions containing the same. In particular, the invention pertains to inclusion compounds of VE, as well as compositions containing the same, which has an effect of further enhancing and prolonging the pungent taste and warm-feeling imparting effect (while VE per se has a pungent taste and warm-feeling imparting effect) and has an effect of further increasing and prolonging the cool or refresh-feeling heightening effect when used in combination with a refrigerant (while VE per se has a cool or refresh-feeling heightening effect when used in combination with a refrigerant).
Ether compounds of vanillyl alcohol are known to exist in the form of a methyl or ethyl ether in vanilla beans as their fragrant component [J. Agric. Food Chem., 26(1), 195(1978]. It is also known that vanillyl alcohol derivatives represented by the above-described formula (I) have a strong pungent taste and warm-feeling imparting effect (JP-B-61-9293) or are effective for enhancement of the refresh-feeling imparting effect of menthol (JP-B-61-55889) (The term xe2x80x9cJP-Bxe2x80x9d as used herein means an examined Japanese patent publication).
Although these VEs have a strong pungent taste and warm-feeling imparting effect, they are accompanied with the problems that their pungent taste is not pure but contains some bitterness, they require a special care upon handling because of having strong stimulation, their solubility in water is markedly low and they tend to be colored with the passage of time.
An object of the invention is therefore to markedly reduce the impure taste, enhance the water solubility, and enhance the stability of VE. Described specifically, an object of the present invention is to provide a novel inclusion compound of VE which has an effect of further enhancing and prolonging the pungent taste and warm-feeling imparting effect (while VE per se has a pungent taste and warm-feeling imparting effect) and has an effect of further increasing and prolonging the cool or refresh-feeling heightening effect when used in combination with a refrigerant (while VE per se has a cool or refresh-feeling heightening effect when used in combination with a refrigerant), and also markedly reduce the impure taste and water solubility of VE; and compositions containing the same.
The present inventors have proceeded with various investigations with a view to overcoming the above-described problems. As a result, it has been found that inclusion of VE in a cyclodextrin (which may hereinafter be abbreviated as xe2x80x9cCDxe2x80x9d) makes it possible to markedly reduce the impure taste of VE and heighten its water solubility and at the same time, to further enhance and prolong the pungent taste and warm-feeling imparting effect (while VE per se has a pungent taste and warm-feeling imparting effect) and to further increase and prolong the cool or refresh-feeling heightening effect when used in combination with a refrigerant (while VE per se has a cool or refresh-feeling heightening effect when used in combination with a refrigerant), leading to completion of the invention. The invention embraces each of the following embodiments of the invention.
(1) An inclusion compound which comprises a cyclodextrin or a branched cyclodextrin and a vanillyl alcohol derivative represented by the following formula (I) having been included therein: 
wherein, R represents a C1-6 alkyl group.
(2) The inclusion compound according to the above-described item (1), wherein the vanillyl alcohol derivative represented by the formula (I) is vanillyl-n-butyl ether.
(3) The inclusion compound according to the above-described item (1), wherein the cyclodextrin is xcex2-cyclodextrin.
(4) The inclusion compound according to item (2), wherein the cyclodextrin is xcex2-cyclodextrin.
(5) A composition which comprises the inclusion compound according to item (1).
(6) A composition which comprises the inclusion compound according to item (2).
(7) A composition which comprises the inclusion compound according to item (3).
(8) A composition which comprises the inclusion compound according to item (4).